A variety of processes which produce FC-114a are known in the art. Representative of these include U.S. Pat. No. 3,231,519 which discloses the preparation of a mixture of 1,2-dichlorotetrafluoroethane (FC-114) and 114a by reacting 1,1,2-trichlorotrifluoroethane (FC-113) with HF in the presence of a catalyst. This process produces more than twice as much FC-114 as it does FC-114a.
Vecchio et al., J. Fluorine Chem., 4 (1974) 117-139, discloses a high temperature fluorination of hexachloroethane or tetrachloroethylene and Cl.sub.2 with HF in the presence of an aluminum fluoride catalyst to produce FC-114a and 1,1,1-triclorotrifluoroethane (FC-113a). In this process FC-114a was produced in 41 mole percent and FC-113a in 20 mole percent, the remainder being unreacted starting material and other fluorination products.
There is growing demand for environmentally desirable fluorocarbons for use as solvents, blowing agents and, particularly, refrigerants. One suitable fluorocarbon particularly useful as a refrigerant is 1,1,1,2-tetrafluoroethane (FC-134a). FC-114a is highly useful as an intermediate in the production of FC-134a. This invention provides a process for producing FC-114a with high selectivity.